Atividade da enzima redutase do nitrato e teores de prolina livre em raízes de cana-de-açúcar sob os estresses hídrico e ácido no solo

The aim of this work was evaluate the physiological indicators of association between water deficiency and soil acidity, by determining the nitrate reductase activity, the levels of free proline and initial growth of the root system of seedlings of sugarcane cv. IAC91-5155. After 30 days, the seedlings were transferred to plastic pots with 12 dm3 of dystrophic alic Red Latosol (Oxisol) and submitted to association of three treatments of water availability: no stress (70%), moderate stress (55%) and severe stress (40%), in according with field capacity and three acidity treatments: no stress (55%), moderate stress (33%) and severe stress (23%), considering the base saturation. The experimental design was that of random blocks under factorial scheme of 3x3, with four replicates. After 60 days under the stress association, the levels of free proline, the nitrate reductase activity and the growth of the sugarcane roots system were evaluated in seedlings of sugarcane. The nitrate reductase enzyme activity can be considered a physiological indicator of the effect of the association of acid and water stress in moderate conditions in soil, while the free proline can be considered physiological indicator to both stress in severe conditions. Water deficiency increasing reduced growth of sugarcane roots.

Parâmetros bioquímicos sanguíneos, balanço de nitrogênio e metabolizabilidade da energia bruta em suínos alimentados com dietas contendo diferentes balanços eletrolíticos

The aim of this study was to evaluate different dietary electrolyte balance (DEB) on the blood biochemical parameters, nitrogen balances and crude metabolizable energy of swine in the initial phase. Sixteen barrows were used, averaging 27.95 kg of initial weight, allotted individually in metabolic cages in a randomized blocks design with four treatments (DEB of 160, 208, 257 and 305 mEq/kg) and 4 replicates. The blood biochemical parameters analyzed were chloride, potassium, sodium and urea in blood. Urine pH was also evaluated, and the parameters evaluated in nitrogen (N) balance were N intake, fecal N, N excreted in urine, absorbed N, N retention, retained N/absorbed N and total excretion of N. The gross energy digestibility and metabolizibility coefficients were determined, and the respectives values of digestible and metabolizable energy. The values of urinary pH increased (P < 0.01) linearly with increasing levels of DEB, ranging from 6.90 to 8.03. The results for chloride, potassium and nitrogen balances of variables and gross energy were similar (P > 0.05) between the evaluated DEB. A linear increase (P < 0.01) was also observed for sodium concentrations in blood serum due to the increase of DEB, with values of 2.91, 3.03, 3.27 and 3.18 g/l, respectively for the different treatments. Urea levels in blood serum increased linearly (P < 0.01), with values of 26.21, 28.64, 34.32 and 32.89 mg/dl. It was concluded that increasing the dietary electrolyte balance, from 160 to 305 mEq/kg resulted in higher concentrations of urea and sodium in blood serum, and higher pH values in the urine of swine in the initial phase.

Resposta metabólica de pacientes cirróticos (Child A) ao aumento da ingestão protéica e/ou calórica. Estudo do balanço nitrogenado.

The dietary protein assimilation by cirrhotic undernourished patients (lower lean body mass and plasma TBPA and RBP levels) was investigated in five-adult male subjects suffering from histologically diagnosed liver cirrhosis, in its clinically mild stage (Child-Turcotte-Pugh grade A). During the 9 day-dietary study the patients received orally a sequence of complete-regional diets containing different protein-energy compositions identified as (g prot/Cal/kg/day): D0 = 0.42/20.9; D1 = 0.91/37.5; D2 = 0.99/47.9 and D3 = 1.60/40.5. The respective N-balance values (g/day) found were (mean +/- SD): low protein calorie (D0) = -4.24 +/- 2.46; normal protein calorie (D1) = 0.66 +/- 1.99; normal protein-high calorie (D2) = 1.14 +/- 2.54; high protein normal calorie (D3) = 5.12 +/- 2.48. The correspondent urea-N output (g/kg/day) were D0 = 0.22 +/- 0.100; D1 = 0.238 +/- 0.099; D = 0.20 +/- 0.063 and D3 = 0.310 +/- 0.121. The present data thus suggest that protein rather than energy intake would be the limited factor for increasing the N-retention in (mild) cirrhotic patients whom tolerate well dietary protein at either normal or elevated levels.

Efeitos nutricionais da substituição parcial do farelo de soja por uréia, em dieta de ovinos. Comparação da digestibilidade aparente e balanço de nitrogênio com a cinética do metabolismo da 15N-glicina

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Balanço de radiação em cultivos de feijão-vagem com e sem cobertura de polietileno

The radiation budget in agricultural crops is very important on the microclimate characterization, on the water losses determination and on dry matter accumulation of vegetation. This work describes the radiation budget determination in a green beans crop (Phaseolus vulgaris L.), in Botucatu, SP, Brazil (22° 54′S; 48° 27′W; 850 m), under two different conditions: the normal field culture and in a polyethylene greenhouse. The densities of fluxes of radiation were used to construct diurnal curves of the components of global radiation (Rg), reflected radiation (Rr), net radiation (Rn).The arithmetic's relations allowed to obtain the components net short-waves (Rc) and net long-waves (Rl). The analysis of these components related to the leaf area index (LAI) in many phenological phases of the culture showed Rg distributed in 68%, 85%, 17% and 66%, 76%, 10% to Rn, Rc and Rl in the internal and external ambients in a polyethylene greenhouse, respectively.

Intervalo hídrico ótimo e produtividade de cultivares de soja

The objective of this study was to determine the optimal water interval and its relationship with soybean yield. For this study, an experiment was carried out in Jaboticabal, São Paulo State, Brazil, in a Haplustox medium textured soil. The experimental design consisted of a completely randomized with subdivided plots (six compaction levels and four soybean cultivars), with four replications. The soil compaction levels were: T 0 = 0, T 1* = 1, T 1 = 1, T 2 = 2, T 4 = 4 and T 6 = 6 strides of a 11 ton tractor, on the same place, side by side on soil surface. In T 1* the compaction occurred when the soil was dry. In December, 2003 the soybean (Glycine max), cultivars IAC Foscarin 31, MG/BR 46 (Conquista), BRS/MG 68 (Vencedora) and IAC 8 - 2 were sown. After sowing, indeformed soil samples were collected in layers of 0.03-0.06, 0.08-0.11, 0.15-0.18 and 0.22-0.25 m for determination of soil water content and resistance to penetration curve and the optimal water content. According to model, the critical soil bulk density (Dsc) for soybean yield varied between cultivars from 1.56 to 1.64 Mg m -3. The soil bulk density at which the yield of soybean cultivars decreased was greater than the Dsc.

Influência de solos de diferentes texturas no desenvolvimento de plantas de Eucalyptus urograndis submetidas a déficit hídrico

The studies were developed with plants of Eucalyptus urograndis under greenhouse conditions, at Paulista State University (UNESP), Botucatu - SP, from March to July, 2005. The objective was to evaluate hydric stress influence on morphological and physiological characteristics of plants in clayay (1) and medium (2) soil texture. Two water treatment were used: -0.03 and -1.5 MPa minimum soil water potentials (□w). Plants from soil 2 and - 1.5MPa showed 43% reduction on leaf área, 34% on base stem diameter, 54% on aerial vegetal dry matter and plants from soil 1 presented 42.3% reduction on leaf área, 39,5% base stem diameter and 42% dry matter root reduction in relation to -0.03 MPa. The lowest leaf water potential (□f) value was-17.166 MPa on □w = -1.5 MPa and soil 2 and the greatest one on soil 1 and □w = -0.03 MPa., -6.766 MPa. The treatment -0.03MPa showed about 11,3% higher transpiration values than those plants from -1.5MPa. The higher Rs value (2.149 s.cm-1) occurred on plants under -1.5MPa and soil 2. There was significant correlation between Tf and Rs, and the treatmens from medium soil were more sensitive, reaching until 32°C.

Compactação do solo e intervalo hídrico ótimo no crescimento da parte aérea e produtividade da cultura do milho

The aim of this work was to evaluate the effect of soil compaction caused by tractor wheel traffic on the limiting water range (LLWR), shoot growth and levels of compaction and four replications in a completely randomized experimental design. Soil samples with preserved structure were collected in the layers: 0.02-0.05; 0.08-0.11; 0.15-0.18 and 0.22-0.25m to determine macroporosity, microporosity, total porosity, bulk density, resistance to penetration and LLWR. The evaluated corn parameters were: plant and first spike height, steam diameter, number of spikes per plant, plant dry matter, dry matter of 1000 seeds and seed productivity. The soil compaction restricted all corn parameters except the number of spikes per plant and dry matter of 1000 seeds. The LLWR was reduced by the soil resistance to penetration, even in the tilled soil with bulk density of 1.12 Mg m-3. Only the treatment with 11 Mg tractor, repeated four times on the area, demonstrated bulk density above critical bulk density in the LLWR that was 1.37 Mg m-3, where the seed productivity was significantly smaller.

Balanço preliminar das economias da América latina e Caribe 2012: documento informativo

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Análise de crescimento em clones de eucalipto submetidos a estresse hídrico

The aim of this study was to evaluate Eucaliptus grandis genotypes (Clones 105 and 433) in relation to drought tolerance, through growth plant analysis. Black PVC pots with 10 liter volume were used for cultivate plants in polyethilene greenhouse oriented east/west. Completely randonmized design with four treatments was used: two clones and two minimum soil water potentials (- 0.03 and -1,5 MPa) and sixteen replicates. Pots were weighed daily in order to evaluate water content and characteristic soli water curve was determined. Plant development was obtained each 15 days from planting until 60 days through total dry matter (DM), leaf area index (LAI), leaf area ratio (LAR), net assimilative ratio (NAR), specific leaf area (SLA), relative growth ratio (RGR) and absolute growth ratio (AGR). Results showed that clone 105 presented less sensibility to water deficit, which qualify it as genetic material for use under dry soil conditons. On the other hand, both clones had similar behavior with no water restrictions.

Características fotossintéticas de genótipos de capim-elefante anão (Pennisetum purpureum Schum.), em estresse hídrico

The experiment was carried out aiming to evaluate the gas exchange of dwarf elephant grass genotypes under different hydric conditions, in a randomized design with three replications. Genotypes of dwarf elephant grass (Mott, CNPGL 94-34-3 and CNPGL 92-198-7) were analyzed under two hydric conditions: irrigated (I) and non-irrigated (NI). Differences between treatments I and NI were observed for all genotypes for photosynthesis, stomatal conductance, transpiration and water vapor pressure deficit. Genotype CNPGL 94-34-3 presented highest tolerance to hydric stress, followed by Mott and CNPGL 92-198-7 genotypes. All genotypes presented high photosynthetic rate, under ideal conditions of soil humidity, thus characterizing the analyzed dwarf elephant grass genotypes as plants with high photosynthetic efficiency.

Acordo sobre a aplicação de medidas sanitarias e fitosanitarias: balanço de uma década buscando o equilíbrio entre a proteção do comércio e a proteção da saúde dos consumidores

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Determinação do índice de estresse hídrico em cultura do feijoeiro com termômetro de infravermelho

In order to calculate the daily stress degree of a bean crop submitted to four water regime applications, cover crop and air daily measurements temperatures were accomplished by using a hand-held infrared thermometer. The treatments did not present crop water stress except the control (without irrigation). The highest yield was obtained by the treatment that received less irrigation frequency, and among the treatments that had the same number of irrigation. The largest yield was obtained with the one that received larger amount of applied water. The largest irrigation frequency did not result in larger productivity. The methodologies used for the irrigation planning were efficient for the replacement of soil water. The daily stress degree index was effective in determining crop water stress; and it was reliable presenting negative values in good water soil condition.

Germinação e vigor de sementes de crambe sob estresse hídrico

This study aimed to evaluate crambe seeds germination and vigor under water stress conditions induced by polyethylene glycol solutions. The seeds were germinated on substrate moistened with polyethylene glycol solutions, using the osmotic potentials of 0 (control), -0.2, -0.4, -0.6, -0.8, -1.0, -1.2 and -1.4 MPa. The seeds germination was evaluated by normal seedlings and root emission percentages. Vigor was evaluated by germination average time, relative frequency, velocity and synchronization index. It was observed that more negative osmotic potential caused significant reduction in crambe seed germination and vigor, and no normal seedlings was observed at potentials below -0.6 MPa.

Inter-relação entre o balanço cátion-aniônico do alimento e o ph urinário de gatos

Studies for the food development of formulations for pets, look for key components to maintaining healthy way of life and safety of products, including these, elements capable of preventing the risk of certain metabolic disorders associated with diet. Feline urinarytract disorders, highlights the urolithiasis, have high incidence in clinical series. Studies linking dietary factors such as ingredients, digestibility and chemical composition, changing the volume, density and pH of urine and consequent induction training for urolithiasis. A highly significant correlation between the mineral composition of the diet and urine pH of cats began to be studied, using the association between the cation-anion balance of the diet (DCAB) and regulation of acid-base balance of the body. The DCAB can be defined as the difference between the total fixed anions and cations present in the diet, important tool for estimating the urinary pH and to determine the range of pH that favors the food used, thereby linking the trigger and the prevention of struvite and calcium oxalate urolithiasis in the urinary tract of cats. Thus, this review aims to clarify the effects of the nutritional composition of diet on urine pH in cats.